Safety control equipment for fluid pressure brakes



SAFETY CONTROL EQUIPMENT FOR FLUID PRESSURE BRAKES Filed Oct. 21, 1949 A. T. GORMAN July 3, 1951 2 Sheets-Shae 1 JNVENTOR.

I Andi'ew IGormar a"?! ATTORNEY July 3, 1951 A. T. GORMAN 2,553,342

SAFETY CONTROL EQUIPMENT FOR FLUID PRESSURE BRAKES Filed Oct. 21, 1949 2 Sheets-Sheet 2 100 Q7 99 Q 8 Q5 95 INVEN TOR.

A 7' TOPNE Y Andrew I Gonnan Patented July 3, 1951 SAFETY CONTROL EQUIPMENT FOR FLUID PRESSURE BRAKES Andrew T. Gorman, Pitcairn, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application October 21, 1949, Serial No. 122,655

Claims.

This invention relates to fluid pressure brake equipment and more particularly to the type for use on railway locomotives.

The 24 RL Locomotive Brake Equipment shown and described in Westinghouse Air Brake Companys instruction pamphlet No. 5066 dated March 1948, and which equipment is similar to that disclosed in Patent No. 2,256,283 issued on September 16, 1941 to E. E. Hewitt et al., is for use on all types of present day locomotives including those employed in connection with the modern high speed trains on which the fluid pressure brakes are normally controlled on the electro-pneumatic straight air principle but which may be controlled on the purely pneumatic principle.

Forming a part of such brake equipment is a dead mans safety control arrangement comprising a brake application valve device which is automatically operative upon a reduction in pressure in a chamber to eifect an automatic service application of brakes on the train. In'order to prevent such operation of the brake application valve device when an application of brakes is not desired it is necessary that the engineer on the locomotive hold depressed safety control means either in the form of a foot treadle or a handle of his automatic brake valve device, since the release of either, with the other released, will cause venting of the chamber of the brake application valve device. To relieve the engineer of holding the treadle or handle depressed when an application of brakes, sufficient to insure the safety of the train, is in effect, a cut-off valve device is provided to close the venting communication from the chamber of the brake application valve device controlled by the treadle and engineers brake valve handle.

The engineers brake valve device comprises the usual automatic portion including a rotary valve having the usual release, running, first service, lap, service and emergency positions for controlling the application and release of brakes on a train through the medium of a brake pipe in the usual manner, and a self-lapping straight air portion for controlling the brakes on the train on the electro-pneumatic straight air principle, a single handle being employed to selectively operate either of said portions according to the position of a selector handle on the side of the brake valve device. Moreover, when the selector handle is positioned to provide for electro-pneumatic straight air control of the brakes, movement of the brake valve handle to its emergency position will effect an emergency reduction in pressure in the usual brake pipe and operation of the rotary valve out of its running position to its lap position to cut off supply of fluid under pressure to the brake pipe, whereby an emergency applica tion of brakes will be obtained.

If, when the selector handle on the brake valve device is in the position to provide for electropneumatic straight air control of brakes on the train, the brake valve device is operated to effect such an application, but the application fails to materialize for any reason, such as due to a broken train wire, a brake application may positively be obtained so as to insure stopping of the train by moving the brake valve handle to its emergency position for venting the brake pipe. The use of emergency position of the brake valve device for bringing a train to a stop is however objectionable on certain railroads except as a last resort.

Moreover, movement of the selector handle to the position for providing usual service control of the brakes by the rotary valve through the medium of the brake pipe at a time when an electropneumatic straight air application of brakes fails to materialize is considered hazardous by certain railroads on account of the delay involved in obtaining the application. To avoid such delay in case of failure of the electro-pneumatic straight air apparatus to operate as intended and also to avoid having to effect an emergency application of brakes to bring the train to a stop it is therefore desirable to effect a service application of fluid pressure brakes on a train by release of the brake valve handle or foot treadle to cause operation of the brake application valve device to effect a service reduction in pressure in the brake pipe and thereby a service application of brakes on the train. If, however, the brake valve handle remains in the position for effecting an electro-pneumatic straight air application of the brakes when it and/or the treadle is released to effect a safety control service application of brakes, the cut-01f valve device will operate, when the brakes are applied to its operating pressure, to close the vent from the chamber of the brake application valve device controlled by the brake to to open the chamber in the brake application valve device again to atmosphere by way of the brake valve handle and treadle, and a reapplication of brakes will occur to the degree where the cut-off valve device will again operate to cause a release of suchapplication. The brakes will thus alternately apply and then release to a low degree with the result that the train will not be brought to a stop as desired. Such alternate application and release of brakes on the train would not occur if the brake valve handle were returned to its running position when an electro-pneumatic straight air application of the brakes failed to materialize since in the running position the chamber of the brake application valve device would remain vented through a valve in the brake valve device with said application valve device in the position for efiecting an application of brakes until the engineer himself desired to release such an application, but under the conditions set forth it is not practical to expect the engineer to return his brake valve handle to running position.

The principal object of the invention is therefore the provision of means adapted to be added to the24 RL Locomotive Brake Equipment for insuring an automatic service application of brakes upon release of pressure by the operator on the brake valve handle or foot treadle and with the brake valve handle in a position for effecting an electro-pneumatic straight air application of brakes and which means will have no eifect upon or change in any way other operating characteristics of the brake equipment.

Other objects and advantages will become apparent from the following more detailed description of the invention.

In the accompanying drawings; Figs. 1 and 2, when the right hand edge of Fig. 1 is matched to the left hand edge of Fig. 2, is a diagrammatic view, partly in section and partly in outline, of a locomotive brake equipment embodying the invention; Fig. 3 is a sectional view taken on the line 33 in Fig.. 1; and Fig. 4 is a view similar to a portion of Fig. 1 but with a part in a different control position.

Description The brake equipment shown in the drawing, except for a portion'thereof constituting the invention, may be identical to that fully disclosed in the instruction pamphlet before referred to and generally similar to that disclosed in the hereinbefore referred to patent, in view of which only such parts of said equipment are shown in the drawings as are deemed necessary to a clear understanding of the invention.

' In the drawings, the reference numeral I designates ,a brake pipe and numeral 2 designates a straight air pipe both of which pipes are adapted to extend through a train and through the medium ofwhich the brakes on the train are adapted to be controlled either on the purely pneumatic principle or on the electro-pneumatic straight air principle, respectively.

Reference numeral 3 designates abrake cylinder device arranged to be operated by fluid under pressure for applying the brakes on the locomotive and such fluid may be obtained, for example, either from the straight'air pipe 2 through one end of a double check valve device 4 or from a brake controlling valve device 5 connected to the opposite end of the double check valvedevice and Which is adapted 'to respond to a reduction in pressure in the brake pipe I for supplying such fluid.

The reference numeral 6 designates a master switch device adapted to operate upon supply of fluid under pressure to a straight air control pipe 1 to energize an application train wire 8 for, effecting energization of an application magnet device 9 to supply fluid under pressure to the straight air pipe 2. The straight air pipe 2 is connected to the master switch device 6 so that said switch device will operate in response to increase in pressure in said pipe to a degree slightly exceeding that in the straight air control pipe 1 to effect deenergization of the application wire 8 and thereby of the application magnet device 9 to terminate supply of fluid under pressure to the straight air pipe 2 and thereby to the brake cylinder device 3. Upon a reduction in pressure in the straight air control pipe 1 pressure of fluid in the straight air pipe 2 will operate the master switch device 6 to effect deenergization of a release control wire Ill and thereby of a release magnet device II to release fluid under pressure from the straight air pipe 2 to a degree corresponding to the reduction in pressure in the straight air control pipe 1.

It will thus be seen that in response to variations in pressure in the straight air control pipe I, the master switch device 6, as controlled by such pressure and the pressure 'of fluid in the straight air pipe 3, will control the application and release magnet devices 9 and II to effect corresponding variations in pressure in the straight air pipe 2 and the brake cylinder device 3 and thereby corresponding degrees of brake application on the locomotive.

In a train, application and release magnets, like 9 and I I, on each car of the train will operate in synchronism with those on the locomotive for effecting like degrees of brake application on said cars, such control of the brakes on a train constituting What is known as electro-pneumatic straight air control.

Operation of the brake controlling valve device 5 in response to a reduction or increase in pressure of fluid in brake-pipe I to either supply fluid under pressure to or release fluid under pressure from, respectively, the brake cylinder device 3 constitutes what is known as control of brakes on the purely pneumatic principle, it being understood that on each car of thetrain therewill be a brake controlling valve device, such as 5, arranged for control by pressure of fluid in said brake pipe on the car whereby through the medium of 'said brake pipe the brakes on all cars of the train may be controlled.

The brake pipe I and'st'raight air control pipe 1 are connected to an engineers brake valve device designated generally by the reference numeral I2.

The engineers brake valve device l2 comprises an automatic brake control portion l3 for controlling the brakes one train through the medium of brake pipe'l a self-lapping straight air control valve device [4 for controlling the brakes-on the train through the'medium of the straight air pipe 2, an emergency valve device l5, an equalizing discharge valve device [6,"a brake pipe cut-off valve device I! and a brake application valve device l8.

Thebrake valve device 12 further comprises -'a vertically disposed "shaft 19 suitably journaled in the casingandconnectedto-said shaft for rotating same is av handle 20'movable in -'a horizontal plane to release, running, first service, lap,

and emergency positions, as designated by suitable legends in Fig. 3. The handle 20 is fulcrumed for vertical movement relative to shaft I9 on a pin 2I carried by said shaft. During running of a train with the brakes thereon released either the handle 20, or a device to be subsequently described, is adapted to be held in a. depressed position. With handle 20 depressed, in which position it is shown in the drawing, a spring 22 carried by the shaft I9 is compressed. Upon release of manual pressure on handle 20 the spring 22 is adapted to turn said handle about the pin 2| for opening a valve 23 to establish a vent from a chamber 24 containing said valve to atmosphere. With handle 20 in its normal depressed position the valve 23 will be closed.

Mounted on one side of the brake valve housing is a selector handle 25 for selectively connecting either the automatic brake control portion I3 or the self-lapping straight air control valve device I4 to shaft I9 for control thereby. In the straight air position of the selector handle 25, the self-lapping straight air control Valve device I4 will therefore be operable by shaft I9 and the automatic brake control portion I3 will not be operable, while in the automatic position of said handle, the latter portion will be operable by said shaft and the former portion not operable.

The automatic brake control portion I3 comprises a rotary valve 26 adapted when the selector handle 25 is in its automatic position to be turned by the handle 20 to positions corresponding to those of said handle indicated in Fig. 3. In running position of handle 20 and the rotary valve 26 a cavity 21 in said valve establishes communication between a passage 28 adapted to be supplied with fluid under pressure from a feed valve device 29 in the usual manner, and passages 30 and 3|, the passage 30 leading to the brake application valve device I8 and to the brake pipe cut-off valve devic I1, while the passage 3| leads only to the brake application valve device I8. In service position of the rotary valve 26 (Fig. 4) the communication just described is adapted to be closed, passage 30 is adapted to be lapped by the rotary valve 26, while passage 3| is adapted to be connected via cavity 32 in said rotary valve to an atmospheric vent port 33. In lap position of the handle 20 and rotary valve 26 the passage 33 is also adapted to be lapped by said rotary valve.

When the selector handle 25 is in its straight air position providing for control of the selflapping straight air control valve device I4 to regulate pressure of fluid in the straight air control pipe I the rotary valve 26 is adapted to remain in running position in which it is shown in Fig. 1 during operation of the handle in a brake application zone extending between the running and service positions in Fig. 3, but upon movement of the handle 20 to emergency position the rotary valve 26 is adapted to be moved from its running position to its lap position. By movement of the handle 20 in the application zone just mentioned the self-lapping straight air control valve device I4 is adapted to provide fluid in the straight air pipe 'I at a pressure proportional to the distance said handle is .out of its running position.

The emergency valve device I5 comprises a valve piston 34 arranged to cooperate with a seat in the brake valve casing for controlling communication between a passage 35 connected to brake pipe I and a chamber 36 which is open to atmosphere through a passage 31. The valve piston 34 is normally urged to its seat for closing the communication just mentioned by a spring 38 and pressure of fluid in a chamber 39 which is open to the passage 35 through a choke 40. The valve piston 34 is provided with an axial bore opening chamber 39 to chamber 36 and. slidably mounted in this bore is a fluted stem of a valve 4I contained in chamber 39 and normally urged to its seat against said valve piston by a spring 42, said stem extending into chamber 36 for engagement by a plunger 43 slidably mounted in a suitable bore in the casing in alignment with a cam 44 provided on the shaft I9. When the handle 20 is turned to emergency position the cam 44 is operative to actuate plunger 43 to first unseat valve 4| for releasing fluid under pressure from chamber 39 followed by engagement of said plunger with said valve piston to open said valve piston for thereby opening passage 35 and the brake pipe I to atmosphere by Way of passage 31 for effecting an emergency reduction in pressure in said brake pipe. Except in emergency position of brake valve handle 29 the valve piston 34 is adapted to be seated as well as the valve 4 I.

At the opposite side of shaft I9 is a poppet valve 46 contained in a chamber 41 open to a passage 48 and having a fluted stem extending through a suitable bore in the casing into a chamber 49 for engagement with a cam 50 provided on said shaft. In release, running and first service positions of handle 20 the cam 59 is adapted to open valve 46 while in the other positions of said handle the valve 46 is adapted to be seated by a spring 5I. Chamber 49 is open to atmosphere through a passage 52.

The equalizing discharge valve mechanism I6 comprises a piston 54 at one side of which is a chamber 55 open by way of a passage 56 to the brake application valve device I8 and to an equalizing reservoir 51. At the opposite side of piston 54 is a chamber 58 open by way of passages 59 and 60 to brake pipe I and into which projects a stem 6I from said piston. Connected to the stem BI is the end of one arm of a bell crank 62 fulcrumed at its knee on a pin 63 secured in the casing. Connected to the other arm of thebell crank 62 is a brake pipe discharge valve 64 for controlling communication between the brake pipe chamber 58, and thereby the brake pipe I, and an atmospheric vent passage 65.

The brake pipe cut-off valve device II comprises a valve 61 arranged to cooperate with a seat 68 for controlling communication between passage 30 and the brake pipe passage 60. The cut-off valve 61 is secured to one end of a stem 69 connecting said valve to a piston Ill subject on one side to brake pipe pressure from passage 60 and on the opposite side to pressure of fluid in a chamber II and that of a spring I2 contained in said chamber. Chamber 'II is connected to a passage 13 leading to the brake application valve device I8.

The brake application valve device I8 comprises a piston I5 at one side of which is a chamber I6 while at the opposite side is a valve chamber 11 adapted to be constantly supplied'with fluid under pressure. A restricted port I8 through piston I5 provides for charging of chamber I6 with fluid under pressure from the valve chamber I1. Contained in the valve chamber II is a slide valve I9 connected for movement by and with the piston 15 through the medium of a stem 80i When chamber 16 is supplied with fluid at sufficient pressure via port I8, a spring 8| contained in said chamber is adapted to move the piston "-15 and slide valve 19 to a normal position in which they are shown in the drawing. Upon venting of fluid under pressure from chamber I6 at a rateexceeding the supply through the restricted port 18, the pressure of fluid in .chamher 1 I is adapted to move said pistonand thereby the slide valve 79 against spring V8! to .a brake application position defined by contact between saidpiston'and a gasket 82.

The brake application slide valve I9 hasa cavity-83 for in the normal position of said valve establishing communication between passage 3.I from the rotary valve 26 and passage 59 leading to the'e'qualizing reservoir 5! and to position chamber 55 in the equalizing discharge valve mechanism I5, while in the brake application position of said valve this communication is adapted to be closed and the passage 56 connected toa reductionlimiting reservoir 9| by way of apassage 90a, a cavity 84 in said slide valve and a restricted port 85 connecting said cavity to the cavity 83. The slide valve 19 also has a passage 89 for in the normal position of said valve opening passage 30 from the rotary valve to passage I3 and in the brake application position of said valve this communication is closed and passage 89 opens passage 48 to-a passage 81 which is connected to piston chamber 76. In the brake application position of slide valve 19 a passage 88 and cavity 89 in said valve are arranged to connect passage 13 from the brake pipe cut-off valve device I] to an atmospheric vent portBdd, while in the normal positionof said slide valve a port 90 open to cavity 89 is arranged to open passage 90a to the atmos-'- pheric vent port 94a, the passage 90a being connected to the reduction limiting reservoir 9 I.

The passage 81 is connected to a pipe 92 leading to a chamber 99 in an application insuring valve device 94. The insuring valve device 94 comprises a valve 95 containedin chamber 93 and arra'ngedto control communication therebetween and a-chamber 96. lhe valve 95 is connected'for movement to one end of a stem 91 extending through a'suitable bore in a partition wall 98 separating said chamber from a chamber 99 which is open .to atmosphere through aport I09. Secured to the opposite end of stem 91 within chamber 991s a follower head-I! engaging one'si'ole of a flexible diaphragm I02, At the opposite side of diaphragm I02 is a pressure chamber I03 which is connected by a pipe I04 to, for example,- the brake cylinder device 3 whereby when an applicationof brakes is in effect on'the locomotive the diaphragm I02 will be subject in chamber I03 to fluid at brake applyingpressure. The side of diaphragm I02 opposite chamber I03 is subject to atmospheric pressure in chamber 99 as will be seen. A-spring I05 contained in chamber 99 acts on the follower head I9I and therebythe diaphragm I02 witha chosen degree of pressure such as tohold diaphragm I92 in theposition in which it is shown in the drawing tohold the valve 95 open until suflicient pressure is obtained in'the brake cylinder device- 9 to insure'the safety of. the locomotive. Any further'increase intpressure in chambe IUS will then deflect the diaphragm I02 againstspring I05 to close valve 95 and thereby communication between chambers 93 and-96. At a lo'werpressure the spring I05 .will actuate-the diaphragm .Iflz toopen valve 95. In practice, the diaphragm-l02 maybe thus. actuated by pressure cer um inichamber :03V to close the valve 95 when- 9 such pressureis for example around 30 pounds and to permit opening of said valve by spring l0'5 when such pressure isaround 20 pounds.

Chamber 96' in the insuring valve device .94 is connected by a pipe .I'0'l to a treadle valve device I08 comprising a treadle I09 adapted to be depressed by the engineer to actuate a diaphragm III) for closing communication between said pipe and a pipe I:I.I when the brakes on the locomotive: and cars of a train are released or applied to .a degree 'less than required to close valve 95 inthe insuring valve device 94. Upon release of pressureontread'le I09 the diaphragm I I0 is adapted to deflectout .of the position in which it is shown in the drawing for opening communication between pipes I01 :and I4. The pipe I4 is connected to passage .24 provided in the brake valve device above thelhandle 20 byway of a passage II In extending through the brake valve device, whereby depression of .the handle 20 to permit closingof valve'23 will serve the same purpose as depression of .the treadle I09. The depression of either the treadle 109 or the brake valve handle 29 willaccomplish the same end whereby either one or the other maybe depressed, as required to relieve the engineer,- butboth need not be held depressed at the :same time.

Operation In operation, let it be assumed that the valve chamber H of the brak application valve device I8 is charged with fluid under pressure and that either the treadle I09 or the brake valve handle 20 is depressed. Under this conditionfluid under pressure from valve chamber TI will equalize, through port "I8 into piston chamber E9 of the brake application valve device and thenthrough the-passage 81, pipe92 and past the open valve 95 in the cut-01f valve device 94 (assuming that the brakes on the locomotive are not applied) into chamber 96 and pipe I01 or through said pipe into p pe I depending upon whether the .trea-j dle I09 or brake valve handle 20 is depressed. When the pressure of fluid in piston chamber 16 is thus sufiiciently increased, spring 9I will move the piston I5 and slide valve I9 to their normalposition in which theyare shown in the drawing and in which cavity 89 will open passage 3I to; passage56, cavity 86 will open passage 30 to passage I3 and port and'cavity 89 will open'the reduction limiting reservoir 9i to atmosphere by way of the atmospheric port 890..

Let it further be assumed that the brake valve handle 20 is in running position whereby the. rotary valve 26 will be likewise positioned regardlessof the position of the selector handle 25. With the rotary valve 26 in running position, fluid under pressure supplied by the feed valve device 29 to passage 28 will flow therefrom through cavity 21 in said rotary valve to passage 3| and then through cavity .93 in the brake application slide valve 19 to passage 59 leading to the equalizing reservoir 51 and the equalizing piston chamber 55 whereby said reservoir and chamber will become-charged with fluid at the pressure suppliedby said feed valve device. At the sametime, .fluid supplied by the feed valve device-to cavity 2'I in therotary valve 26 will flow to passage 30 and thence to the cut-off valve 9'! as well as through cavity 86 in the brake application slide valve 19 to. passage I3 leading to pistonchamber II of the cut-off valve device I7. Withpiston chamber II thus charged withfluid at the pressure-supplied by thefeed valve device, spring-7.2- will .actuateipiston :10 to open valve 97. wherebyfluid at feed valve pressure present in passage 30 will flow past said valve to passage 60 and thence to chamber 56 in the equalizing discharge valve mechanism It and to the brake pipe I for charging chamber 58 and said brake pipe. The brake controlling valve device will operate to its release position in response to this charging of brake pipe I to open to atmosphere its pipe connection with the double check valve 4. With the brake valve handle 20 in its running position, the self-lapping straight air control valve device I4 will operate to open the straight air control pipe I to atmosphere whereby through the medium of the master switch device 6 and the application and release magnet valve devices 9 and I I the straight air pipe 2 and its connection to the double check valve device 4 will be vented. The brakes on the locomotive will thus be released.

Now assuming that the selector handle 25 is in its straight air position, if the brake valve handle 20 is moved out of its running position in the direction of service position the self-lapping straight air control valve device I4 will operate to supply fluid to the straight air control pipe I at a pressure corresponding to such movement for thereby effecting operation of the master switch device 6 and application magnet device 9 to supply fluid at a corresponding pressure to the brake cylinder device 3 to effect an application of brakes. If the handle 20 is returned to running position the self-lapping straight air control valve device I4 will operate to release such an application of brakes.

Now let it be assumed that the selector handle 25 is in its automatic position and that the brake handle 20 is moved from running position to service position. The rotary valve 26 will thereby be moved to the position in which it is shown in Fig. 4 for cutting off supply of fluid under pressure from the feed valve passag 28 to passage 30 and thence to the brake pipe I and for at the same time releasing fluid under pressure from the equalizing reservoir 51 and equalizing piston chamber 55 to atmosphere via cavity 32 in said rotary valve and passage 33. In response to such reduction in pressure at one side of the equalizing discharge valve piston 54, brake pipe pressure acting on the opposite side in chamber 58 will move said piston in the direction of chamber 55 for thereby actuating bell crank 62 to open the brake pipe discharge valve 54 for releasing fluid under pressure from the brake pipe I, in response to which the brake controlling valve device 5 will operate to supply fluid to the brake cylinder device 3 to apply the brakes on the locomotive to a degree proportional to the reduction in pressure in the equalizing reservoir 51. If less than a full service application of brakes is desired, then when the desired reduction in pressure in the equalizing reservoir 51 and piston chamber 55 is obtained, the handle 20 will be moved from service position back to lap position for closing oif discharge of fluid from said reservoir and chamber whereby when the pressure of fluid in brake pipe I acting in chamber 58 at the opposite side of equalizing piston 54 becomes reduced to slightly below that in chamber 55, said piston will operate the bell crank 62 to close the discharge valve 64 for thereby limiting the reduction in pressure in brake pipe I to a corresponding degree, and the Pressure of fluid obtained in the brake cylinder 3 to a proportional degree, in a Well-known manner.

When the pressure of fluid obtained in the brake cylinder device, 5 by operation of either rotary valve 26 or of the self-lapping straight air control valve device I 4 is suificient to insure stopping of the train, such pressure acting in chamber I03 of the application insuring valve device 94 will deflect diaphragm I02 to close valve 95 for thereby closing communication between chamber I6 in the brake application valve device I8 and the treadle valve device I08 whereupon pressure of the engineer can be relieved on treadle I09 or brake valve handle 20, whichever has been held depressed, without venting fluid under pressure from piston chamber I6. However, if the degree of brake application is insufficient to close valve 95 in the insuring valve device 94 and pressure of the engineer is relieved on both the treadle I09 and brake valve handle 20, the pipe I01 and thereby pipe 92 connected to the brake valve device will both be vented through the insuring valve device 94, the-foot valve device I08, and past the open valve 23 controlled by the brake valve handle 20. As a result, fluid under pressure will be vented from piston chamber I6 in the brake application valve device I8 and the piston I5 will operate to move the slide valve I9 to its brake application position.

When the slide valve I9 is thus moved to its brake application position piston chamber II in the cut-off valve device II will be vented through passage in the application slide valve 11 and the atmospheric passage 84a as a result of'which brake pipe pressure acting on the opposite side of piston I0 will actuate said piston to close valve 61 and thereby the communication through which fluid under pressure is normally supplied to the brake pipe. At the same time the equalizing piston chamber 55 will be disconnected from passage 3I leading to the rotary valve 26 and opened through cavities 83, 84 and restricted port 85 in said valve to passage a leading to the reduction limiting reservoir 9I whereby the pressure of fluid in the equalizing reservoir 51 and equalizing discharge valve piston chamber 55 will reduce to equalization into said reduction reservoir and the discharge valve mechanism I6 will operate to effect a service reduction in pressure in brake pipe I for causing operation of the brake controlling valve device 5 to supply fluid to the brake cylinder device 3 to effect a service application of brakes on the locomotive. The volume of the reduction limiting reservoir 9| may be such that the reduction in pressure in the equalizing reservoir 51 due to equalizing into said limiting reservoir will be sufficient to insure a full service application of the brakes on the locomotive.

In the brake application position of the brake application valve device I8, piston chamber I6 is connected by way of passage 81 and passage 86 in the slide valve I9 to passage 48 leading to the poppet valve chamber 41 in the brake valve device whereby with the poppet valve 46 open in the release, running and first service positions of the brake valve handle 20, the application piston chamber I6 will remain vented even upon subsequent depression of the treadle I09 or depressing of handle 20, to insure a full service application of brakes on the locomotive and thereby stopping ofthe locomotive and connected'train in case of incapacitation of the engineer or failure to maintain the treadle I09 or handle 20 depressed as intended to safeguard the locomotive and train. If, however, the handle 20 is moved past the first service position at the time the treadle I09 and/or handle 20 are relieved of pressure, the poppet valve 46 will be closed so that even though the brake application piston I5 and slide valve '79 move to their application position; the pressure of fiui'dobt'ained in the brake cylirider device 3 and thereby in chamber 103 of the insuring valve device li l; either by operation of the straight air control valve device It or rotary valve 26, will eventually become sufiicient to operate said insuring valve device to close valve 95 whereby piston chamber I6 of the brake application valve device will be recharged with'fluid under pressure to permit springBI to return piston'15 and slide'valve I9 to their normal position.

"Regardless of the position of the selector handle 25, the* brake valve handle 20 upon movement to its emergency position will effect opening-of the emergency valve piston 34 for thereby effecting a sudden emergency reduction in pressure in brake pipe'I for in turn causing operation of the brake controlling valve device to supply "fluidunder pressure tothe brake cylinder device 3 to effect an application of brakes on the locomotive for bringing the locomotive to a stop.

Now let it'be assumed'that with the selector handle 25 in its straight air position, the brake valve handle 20 is moved into its application zone for causing operation of the self-lapping straight air'control valve device I4 to effect an electropneumatic straight air application of brakes on the locomotiveybut that such application fails to materialize-due, for instance, tofailure in said valve device or in the master switch device 6 or in the applicationmagnet device II or possibly due to breaking'of the application train wire 8. Under such a condition the engineer may move the handle 20 to its emergency position for effectin'ga'n emergency application of the fluid pressure brakes on the-locomotive, as above mentloned, if he so'desires. 'If, howeven'under such a condition the handle 20 is allowed to remain in its'brake application zone past first service position in which the poppet valve 46 is closed and the engineer removes pressure on the brake valve handle"20 and/or treadle'lll9 for venting fluid underpressure from the application piston chamber T6, the application piston 15 and slide valve -'I9:wil'l moveto application position. In the application positionof slide valve 19 the cut-off valve device will operate to cut-01f further flow of fluid underpressure to the brake pipe I and at the same time the equalizing discharge valve mechanism' I6 will also operate as hereinbefore described to reduce the pressure of fluid in the brake pipe I for in turn causing operation of the brake controlling valvedevice 5 to supply fluid under pressure .tothe brake cylinder device 3 to apply the locomotive brakes and such pressure will become effective through pipe I94 in diaphragm I03 of the insuring valve device 94. When the pressure of fluid thus obtained in the brake cylinder device 3 becomes suflicient' to deflect'diaphragm I02 in the insuring valve device 9'4-"forc'1osing valve 95, such closure will disconmeet the brake application piston chamber I6 from its atmospheric vent through the operators treadledevice I08 and the open valve 23 controlled by the'b'rake valve handle, as a result of which, the brake application piston chamber I6 will become charged with fluid under pressure by Wayo'f'port' 18 in the piston 15 and spring 9| will return said piston and the slide valve 19 to their normal position. Upon the return of slide valve 19 to its normal position the cut-off valve device 11. will reopen to permit recharging of the brake Dip'e by supply of fluid under pressure through the rotary valve 26 as previously described and the brake controlling valve device'fi'will respond to such recharging to effect release of fluid under pressure from the brake cylinder device 3 and thereby from chamber I93 in the insuring valve device 94. When the pressure of fluid in chamber I03 of the insuring valve device 9 3 is thus sufliciently reduced said device will operate to reopen valve therein for again venting fluid under pressure from piston chamber 16 in the brake application valve device toatmosphere by way of the treadle valve device I08 and valve 23 controlled by the brake valve handle 29. The brake application valve device I8 will then again operate to effect a reduction in pressure in brake pipe I whereby the brake controlling valve device 5 will operate to again supply fluid under pressure to the brake cylinder device 3 until the insuring valve device 93' again operates in response to such pressure to disconnect the brake application piston chamber'lfi from its atmospheric vent through treadle device I98 whereupon the brake application device I 8 will again return to normal position. 'The brake application valve device I8 will thus alternately move to its application position for efiecting an application of brakes on the locomotive and then to its normal position for releasing such application with the result that stopping of the locomotive will be unduly delayed.

In-order to insure that the brake application valve device I8 will not operate'to efiect a partial service application of brakes on the locomotive and then a partial release of such application and cause unnecessarydelay of stopping of the locomotive at a time when the brake valve handle 29 is in a position for causing anelectro-pneumatic straight air applicationof brakes, which however does not materialize, and in which position the valve 46 isclosed, passage 48, according to the invention, is connected to a pipe H2 and thence through a check valve H3 to pipe I0! connecting the insuring valve device 94 to the treadle device I68. The check valve I93 is arranged to permit flow of fluid under pressure from pipe M2 to pipe IB'I, whereby when the application pistonchamber 76 is vented to atmosphere by way of the insuring valve device 94 in response to release of manual pressure on the treadle I99 and brake valve handle 20 such venting will be maintained by way of passage 86 in slide valve 19 and passage 48, pipe I I2 andthrough the check valve device H3 to pipe I0! which will remain open to atmosphere as long as the treadle I99 and brake valve handle 29 are relieved of pressure regardless of operation of the insuring valve device 94, it being noted that this vent from the brake application piston chamber I5 by-passes said insuring valve device. With this arrangement if an el'ctrO-pneumatic straight air application of brakes on the locomotive fails to materialize with the poppet valve 46 closed and the operator removes pressure from treadle I 09 and brake valve handle 2!], operation of the brake application valve device I8 to effect a full service application of brakes is assured even upon closing of valve 95 in the insuring valve device 94.

The check valve I I3 is provided to prevent loss of fluid under pressure from pipe I91 through the open poppet valve 46 in the brake valve device when thebrake valve handle 20 is in release or running position with the brakes released and either the treadle IE9 or brake valve handle '20 is depressed, under which condition the pipe 92 will be charged with fluid under pressurefrom the brake application piston chamber 16 and-be open through the insuring valve device 94 to said pipe I01.

Summary It will now be seen that I have provided means adapted to be associated with the 24 RL Locomotive Brake Equipment for insuring a full service pneumatic application of brakes on the locomotive and connected cars of the train in response to operation of the safety control means on the locomotive in case an electro-pneumatic straight air application of brakes, suflicient to insure safety of the train, fails to materialize.

Having now described the invention what I claim as new and desire to secure by Letters Patent, is: r

1. In a locomotive brake equipment, in combination, means including an operators brake valve device operative to effect an application of locomotive brakes, an operators control device and brake application means operative from a normal position in response to release of manual pressure on said control device to also effect an application of locomotive brakes, application insuring means arranged to respond to a chosen degree of brake application effected by operation of either said brake valve device or said brake application means to disestablish the control connection between said brake application means and said control device and in response to a lesser degree of brake application to establish said control connection, and means for establishing a control connection between said brake application means and control device by-passing said insuring means only with said brake application means operating to effect an application of brakes.

2. In a locomotive brake equipment, in combination, and engineers brake valve device for effecting an application of locomotive brakes, brake application means operable to an application position in response to a reduction in pressure of fluid in a chamber to effect an application of locomotive brakes, and operative to a normal position in response to charging of said chamber with fluid under pressure, means operative upon release of manual pressure to establish a fluid pressure venting communication from said chamber, application insuring means responsive to a chosen degree of brake application to close said communication and to a lesser degree of brake application to open said communication, means for charging said chamber with fluid under pressure with said communication closed, and means cooperative with said brake application means in said application position and with said brake valve device in a position for effecting an application of brakes to establish a vent from said chamber by-passing said insuring means which vent is closed by said application means in said normal position.

3. In a locomotive brake equipment, in combination, fluid pressure operable brake applying means, an engineers brake valve device for effecting supply of fluid under pressure to operate said brake applying means, brake application means operative in response to venting of fluid under pressure from a chamber to a brake application position for effecting supply of fluid under pressure to operate said brake applying means and in response to supply of fluid under pressure to said chamber to a normal position, a double check valve operable by fluid under pressure supplied by operation of either said brake valve device or said brake application means to close communication between the other and said brake 14' applying means, safety control means operative upon release of manual pressure to vent'fluid under pressure from said chamber, application insuring means responsive to a chosen pressure of fluid in said brake applying means to close communication between said brake application valve device and safety control means and responsive to a lesser pressure of fluid in said brake applying means to open such communication, means for supplying fluid under pressure to said chamber, and means cooperative with said brake application means in its brake applying position to establish a communication between said cham ber and safety control means which by-passes said insuring means and which communication is closed by said application means in its normal position.

4. In a locomotive brake equipment, in combination, means including an engineers brake valve device for effecting an application of brakes, a brake pipe, brake controlling means responsive to a reduction in pressure of fluid in said brake pipe to supply fluid under pressure to effect an application of brakes and responsive to an increase in pressure in said brake pipe to release such fluid under pressure, means including brake application means operable upon a reduction in pressure in a chamber to an application position for cutting off supply of fluid under pressure to and for effecting a reduction in pressure of fluid in said brake pipe and operable upon charging of said chamber with fluid under pressure to a normal position for supplying fluid under pressure to said brake pipe, safety control means operative upon release of manual pressure to establish a communication from said chamber for reducing pressure therein, means operative upon closing said communication to charge said chamber with fluid under pressure, application insuring means arranged to be operated by a chosen degree of brake application effected by operation of either said brake valve device or said brake controlling means to close said communication to said safety control means and responsive to a lesser degree of brake application to open said communication, a passageway, said brake application means opening said chamber to said passageway in the application position thereof and disconnecting said passageway from said chamber in its normal position, means for venting said passageway with less than said chosen degree of brake application and for closing such vent with a greater degree of brake application, and one-way flow means opening said passageway to said safety control means in by-passing relation to said cut-off means.

5. In a locomotive brake equipment, in combination, means including an engineers brake valve device comprising a handle for effecting an application of locomotive brakes to a degree corresponding to the extent of movement of said handle from a normal position, brake application means responsive to venting of fluid under pressure from a chamber to a brake application position to effect an application of brakes and responsive to charging of said chamber with fluid under pressure to a normal position, safety control means responsive to release of manual pressure for venting said chamber, means for charging said chamber upon applying manual pressure to said safety control means, application insuring means operative in response to a chosen degree of brake application effected by operation of either said engineers brake valve device or said brake application means to close communication 15 betweensaid brake. applying 'means and safety CDIltIOI means, and-to open said communication for a lessendegree ofbrake application, a passageway, a valve controlled by said brake valve device for opening said passageway to atmosphere with said handle in a position to provide less than said chosen degree of brake application and for closing such communication with atmosphere with said-handle-in a position to provide a greater degree of brake application, a one-way-flow communication opening said passageway around said insuring means to said safety control means, and means including said brake application means for opening said passageway to said chamber in said ANDREW T. GORMAN.

REFERENCES CITED The following references areof record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,166,007 Hewitt et a1 July 11, 1939 2,256,283 Hewitt et a1. V Sept. 16, 1941 

